Geographic Range

White crappies, Pomoxis annularis, can be found in the freshwaters of North America. The species is native to the Mississippi and Great Lakes drainages, also Gulf Slope streams from the Nueces River in Texas east to Mobile Bay and in the Red River tributary to Hudson Bay. A popular game fish, the species has been widely introduced into lakes and streams all across the United States and extreme southern Canada. (Rohde, et al., 2009; Schultz, 2004; Stauffer, et al., 1995; Sternberg and Ignizio, 1996)

Habitat

White crappies are most abundant in reservoirs and freshwater lakes greater than 2 hectares in area, but also occur in smaller ponds and in slow-moving streams and rivers, usually over sand- or mud-bottoms. They prefer shallow waters and are not usually found deeper than the thermocline. In Texas they are found no deeper than 5 m during the breeding season, and move to only somewhat deeper water (6 to 10 m) in the winter. They prefer cool waters, but are tolerant of a range of temperatures. Similarly, they prefer and grow best in clear waters, but can also live in moderately turbid waters. In regions where both white and black crappies (Pomoxis nigromaculatus) are present, white crappies tend to be found in more turbid and warmer waters. They do best in waters with a neutral-to-basic pH ranging from 6.5 to 8.5. White crappies can survive in waters with oxygen levels as low as 3.3 mg/L. They can be found in waters with a maximum salinity of 20 mg/kg. Cover is important for protection against predators, and they gather around submerged rocks and woody debris, and in or near stands of underwater plants. ("Habitat suitability index models: White crappie", 1982; Rohde, et al., 2009; Schorr and Miranda, 1995; Schultz, 2004; Wallus and Simon, 2008)

Physical Description

When white crappies hatch, they are about 4.1 to 4.6 mm long. The juveniles range from 50 - 60 mm in length. By the end of their second year, they average 20 cm in total length. Adult length ranges from 17 cm to 53 cm. The adults weigh between 0.46 - 2.27 kg, with an average weight of 0.91 kg.

The he bodies of white crappies are compressed to allow for quick movement through the water. Their scales are a silvery-olive color with rows of black spots running across their sides and a white belly. Males have darker faces and backs than females. They have noticeable depressions in their forehead. They have five or six tough dorsal fin spines on the fish as well as 14 dorsal rays that are more flexible. Dorsal spine count is a reliable way to distinguish this species from the black crappie, Pomoxis nigromaculatus. White crappies have 5-6 spines, black crappies have 7 or 8. There are also six anal spines and 16 to 18 anal rays on the white crappie. (Mathur, 1972; Rohde, et al., 2009; Sternberg and Ignizio, 1996; Wallus and Simon, 2008)

Development

Upon hatching of the white crappie, the egg dissolves around the embryo and the yolk sac stays attached to its head. Young crappies are identified as larvae at this stage. They remain in the nest until their yolk sac is absorbed which takes 2 to 4 days; afterward, they are known as post-larvae. When the post-larvae leave the nest, they are 4.1 mm to 4.6 mm long and do not join schools. Many die during this stage due to being eaten by predators, or by limited food supply.

Crappies do not develop scales until they are 16 mm to 19 mm long. The scales will start developing on the tail, then on the stomach, and then the rest of the fish. White crappies obtain all their scales in their second year when they reach about 27 mm in length. The young stay in shallow waters where there is plenty of light until they are juveniles in their third year when they are 50 mm to 60 mm in length. Then they travel to deeper waters and join the adults in schools.

Reproduction

White crappies are polygynandrous and spawn in late spring or early summer (varies with local climate and water temperature). Males are first to arrive in the spawning area and make nests in shallow water – about 20 cm to 1 m under the surface – in places where there is cover for protection. Males push out depressions in the mud, sand, clay, or gravel of the bank with their fins and construct a nest about 30 cm in diameter. They surround the nest with twigs for additional cover. Nests are arranged in colonies, but the males are protective of their nest and are aggressive towards other males. Males will chase away intruders and bite them or push them out. They will even show aggression towards females until the females act submissively and do not swim away. They then lead females to the nest so the females can lay their eggs. The male and female will touch each other and release their gametes at the same time. (Cooke and Phillip, 2009; McGinnis, 2006; Michaletz, 2013; Siefert, 1968; Wallus and Simon, 2008)

White crappies are sexually mature at two to three years old. They start spawning in May and June when the water temperature ranges from 14 to 23 degrees Celsius.
Older female crappies produce higher numbers of healthier eggs than younger females. A female holds as many as 232,000 eggs, but does not release them all in one spawn. The average nest holds 27,000 to 68,000 eggs from six to twelve spawnings. The eggs are 0.89 mm in diameter and stick to the bottom of the nest. After the eggs are fertilized, it takes the eggs about 42 hours to hatch in warmer temperatures and 103 hours to hatch in cooler temperatures.

After spawning, females may clean the nest of debris, but they depart immediately thereafter. Males will continue to guard the nests and continue sweeping out debris that falls in the nest with their fins. They protect the eggs and newly hatched young. The young leave the nest immediately after they start swimming, because the male may eat the young. After the post-larvae leave the nest, they are unprotected. (Cooke and Phillip, 2009; McGinnis, 2006; Siefert, 1968)

Lifespan/Longevity

The maximum lifespan of white crappies is 8 to 10 years with the average lifespan being 3 to 4 years in unmanaged waters and 6 years in managed waters. In unmanaged waters, the crappies can become overpopulated or infected with parasites; whereas in managed waters, the remaining crappies are healthier. (McNab, 2002; Schultz, 2004; Wallus and Simon, 2008)

Range lifespanStatus: wild

10 (high) years

Range lifespanStatus: captivity

10 (high) years

Typical lifespanStatus: wild

3 to 4 years

Average lifespanStatus: wild

3 years

Behavior

White crappies are most active in the evening and early morning when they are feeding and are less active throughout the day. When the water is 16 degrees Celsius to 20 degrees Celsius, they swim in shallower waters and retreat to deeper waters when the water cools below 14 degrees Celsius. The fish are active year-round.

Subjection to cold for long periods of time affects their lifespan. Waters that remain below 4 degrees Celsius for more than a week will kill almost half of the crappie population. The cold water affects the fishes’ osmoregulation or its ability to keep its blood from becoming too concentrated with salt from the water.

The fish travel loosely in schools and tend to colonize areas where there is cover such as underwater brush, underwater rock formations, and fallen trees. White crappies stop traveling in schools while spawning, but after spawning they gather and move to deeper water depths for the rest of the year.

Home Range

White crappies have an average home range of 0.56 hectares during the day and an average home range of 1.25 hectares during the night. The schools they travel in tend to stay in the same areas. (Markham, et al., 1991)

Communication and Perception

White crappies are visual hunters that use a hunting tactic where they inspect the area for prey, and if none are found, they swim away from the area and scan a different location for prey. This tactic is known as saltatory searching. When hunting, they are more successful at catching their prey if the prey is located slightly above or to the side of their head. The ability of white crappies to see small prey decreases as the white crappies grow in size. This is caused by the angles of the adjacent cones in their eyes getting smaller and partially explains why they eat zooplankton when larvae, and fish when adults.

White crappies have a lateral line system that helps them detect movement and vibrations in the water.

Food Habits

Young white crappies are filter feeders with large mouths and close-set gill rakers. They are born in the spring and eat zooplankton. As they develop, they are able to devour small crustaceans in the autumn and winter months. At the end of their second year, they are able to eat small fish and insects.

Predation

White crappies are preyed upon by northern pike Esox lucius, walleye Sander vitreus, and largemouth bass Micropterus salmoides. Largemouth bass and walleye only feed on white crappie when they are in the larvae and post-larvae stage. The northern pike feeds on the adults. Sometimes these predators are added to the population by humans Homo sapiens in order to keep the white crappies’ numbers in check. Addition of predators reduces food competition between crappies and allows the survivors to grow larger in size. Other fish such as white bass Morone chyrsops and striped bass Morone saxatilis are additional human-introduced predators. Humans also fish white crappies for sport.

Economic Importance for Humans: Positive

White crappies are caught for sport, and often are included in fisheries' management plans. Local competitions to catch the largest fish may increase tourism and increase the sales of fishing equipment. White crappies are also popularly fished in reservoirs and lakes. In managed waters, such as Fall River reservoir and the Niangua arm of the Lake of the Ozarks, white crappie represent 0.47 percent and 31.74 percent of the fish caught in trap nets respectively.

Economic Importance for Humans: Negative

There are no known adverse effects of Pomoxis annularis on humans.

Conservation Status

Due to the abundance of white crappies in native waters, no conservation measures are considered necessary. They are listed as a species of "Least Concern" on the IUCN Red List. In many parts of their range they are protected to some extent by fishing regulations. (NatureServe, 2013; Schultz, 2004)

Other Comments

Some crappies’ habitats are maintained by the state or by a private owner. These habitats are stocked once a year and surveyed once or twice a year. Surveyors determine how well the crappies’ population is doing based on the lengths of the fish caught and if food is present in their stomachs. They catch the fish in trap nets until they have collected about 150 specimens. Surveyors determine the age of the each fish by looking at the size of their scales. White crappies, that are two years and older, are then measured. An average length of 130 mm or less indicates overpopulation. Another indicator of overpopulation is if the majority of fish caught have empty stomachs.

A voluminous population can be moderated by the introduction of predators, additional prey species, or competing fish species. Introducing prey species such as gizzard shad Dorosoma cepedianum can increase the crappies' length as well as provide another sport fish for anglers. In extreme overpopulation, chemical treatment with rotenone can kill all fish, and then waters can be restocked.

Managing populations of white crappies can be expensive because they need to be surveyed yearly. One billion dollars are spent yearly on maintaining fisheries in the United States.

Contributors

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

freshwater

mainly lives in water that is not salty.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

piscivore

an animal that mainly eats fish

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

zooplankton

animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)

Wallus, R., T. Simon. 2008. Reproductive Biology and Early Life History of Fishes in the Ohio River Drainage, Vol. 6: Elassomatidae and Centrarchidae. Boca Raton, FL: CRC Press.

Willis, D., J. Smeltzer, S. Flickinger. 1984. Characteristics of a crappie population in an unfished small impoundment containing northern pike. North American Journal of Fisheries Management, 4: 385-389.

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The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

This material is based upon work supported by the
National Science Foundation
Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.